Microorganisms come in 3 different forms, Virus, Protista, Bacteria and fungi. They all serve their own purpose good or bad. (Take info from other answers to back up)
The products and reactants of each cycle are connected. reactants of photosynthesis (6O2 and C6H12O6) are recycled as products in cellular respiration which produces 6H2O 6CO2 and energy to fuel photosynthesis
